Selection of optimal combinations of inputs in a partial least squares model for prediction of soil organic matter

Abstract

Partial least squares model is widely used in estimation of soil physical and chemical parameters such as soil organic matter and moisture content, due to its advantages in dealing with collinearity of variables like hyperspectral reflectance. However, it is hard to determine optimal combination of partial least squares model input for soil organic matter prediction since there are lots of possibilities such as, different mathematical transformation of spectral reflectance, wavelength ranges, and spectral resolution. Laboratory hyperspectral reflectance of soils in Songnen plain were analyzed in this study, and the orthogonal experimental design method for deriving optimal combination of input variables for soil organic matter prediction models was introduced. For intercalating orthogonal experimental design table, five different levels which commonly used by researchers were assigned to factors. Results show that the optimal combination input for single black soil is using the derivative logarithmic reciprocal reflectance in the wavelength range selected by multiple stepwise regression at a spectral resolution of 5?nm (R²=?0.95, RMSE?=?0.21, and RPD?=?4.49), and different soils is using continuum removed in the wavelength range selected by MSR at a spectral resolution of 5?nm (R²?=?0.77, RMSE?=?0.74, and RPD?=?2.08). With optimal combination input, the partial least squares model prediction ability was evaluated as excellent for single black soil, possible for different soils. This study illustrates the orthogonal experimental design method can be an effective way to identify the optimal input variables of a partial least squares model for soil organic matter prediction, and multiple stepwise regression can be a preprocessing step to reduce hyperspectral data redundancy before using partial least squares to predict soil organic matter. Overall, this study provides a new approach for determining optimal input of partial least squares predicting model.     

The studies of high-temperature and short-time annealing,phase transition process,and magnetic property for LaFe11.7Si1.3 compound

The high-temperature phase transition is analyzed according to the DSC of as-cast LaFe_11.7 Si_1.3 compound and the X-ray patterns of LaFe_11.7Si_1.3 compounds prepared by high-temperature and short-time annealing. Large amount of 1:13 phase begins to appear in LaFe_11.7Si_1.3 compound annealed near the melting point of LaFeSi phase (about 1422?K). When the annealing temperature is close to the temperature of peritectic reaction (about 1497?K), the speed of 1:13 phase formation is the fastest. The phase relation and microstructure of the LaFe_11.7Si_1.3 compounds annealed at 1523?K (5?h), 1373?K (2?h)?+?1523?K (5?h), and 1523?K (7?h) +1373?K (2?h) show that longer time annealing near peritectic reaction is helpful to decrease the impurity phases. For studying the influence of different high-temperature and short-time annealing on magnetic property, the Curie temperature, thermal, and magnetic hystereses, and the magnetocaloric effect of LaFe_11.7Si_1.3 compound annealed at three different temperatures are also investigated. Three compounds all keep the first order of magnetic transition behavior. The maximal magnetic entropy change ΔS_M (T, H) of the samples is 12.9, 16.04, and 23.8?J?kg^?1?K^?1 under a magnetic field of 0–2?T, respectively.     

Combined Helmholtz equation-least squares method for reconstructing acoustic radiation from arbitrarily shaped objects

A combined Helmholtz equation-least squares (CHELS) method is developed for reconstructing acoustic radiation from an arbitrary object. This method combines the advantages of both the HELS method and the Helmholtz integral theory based near-field acoustic holography (NAH). As such it allows for reconstruction of the acoustic field radiated from an arbitrary object with relatively few measurements, thus significantly enhancing the reconstruction efficiency. The first step in the CHELS method is to establish the HELS formulations based on a finite number of acoustic pressure measurements taken on or beyond a hypothetical spherical surface that encloses the object under consideration. Next enough field acoustic pressures are generated using the HELS formulations and taken as the input to the Helmholtz integral formulations implemented through the boundary element method (BEM). The acoustic pressure and normal component of the velocity at the discretized nodes on the surface are then determined by solving two matrix equations using singular value decomposition (SVD) and regularization techniques. Also presented are in-depth analyses of the advantages and limitations of the CHELS method. Examples of reconstructing acoustic radiation from separable and nonseparable surfaces are demonstrated.     

Correlation Analysis of the Fluorescence Data of Some Benzaldehyde Derivatives by the Dual-Parameter Equation

Ithasbeenrecentlyestablishedthattherearefourcategoriesofpossiblecircumstancesforcorrelati0nanalyses0fradicalreactivitiesandspectralpropertiesbyEq.(l),Eq.(2)andEq.(3)."(I)Bothp0larandspin-del0calisationeffectsaretwortant,O.2l.O.(III)Thespin-delocalizationeffectspredominate,lpmdpJJ'I<0.2.(IV)Nocorrelationcanbeachieved.Wehavef0undthatthebehavi0roffluorescencespectraldataofsomestyrenes,'bycorrelati0nanalysiswiththedual-parameterEq.(…     

Distinguishability and indistinguishability by local operations and classical communication

It is well known that orthogonal quantum states can be distinguished perfectly. However, if we assume that these orthogonal quantum states are shared by spatially separated parties, the distinguishability of these shared quantum states may be completely different. We show that a set of linearly independent quantum states [formula: see text] where U(m,n) are generalized Pauli matrices, cannot be discriminated deterministically or probabilistically by local operations and classical communication. On the other hand, any l maximally entangled states from this set are locally distinguishable if l(l-1)< or =2d. The explicit projecting measurements are obtained to locally discriminate these states. As an example, we show that four Werner states are locally indistinguishable.     

Research on solid-state fermentation on rice chaff with a microbial consortium

A microbial consortium of Trichoderma reesei AS3.3711, Aspergillus niger 3.316 and Saccharomyces cerevisiaes AS2.399 was constructed to decomposed rice chaff on the basis of the characters of each microorganism and the mechanism of cellulases. In this experiment, rice chaff was pretreated before fermentation with NaOH so that the lignin structure of rice chaff was degraded and hemicellulose was dissolved partly, which remove the protection of lignin and hemicellulose on cellulose and demolish its special crystal structure. After pretreatment, rice chaff can be degraded more easily with the microbial consortium. The optimal technical paths and technological methods were achieved for intenerating rice chaff with the microbial consortium perfectly through orthogonal experiment. According to the technological methods, some experiments were done at 30 degrees C with pH 4.5. It was found that the highest filter paper enzyme activity (FPA) was 5.64 U/g and the ratio of cellulose degradation (RCD) was 28.05%.     

Synthesis of silver nanotubes by electroless deposition in porous anodic aluminium oxide templates

An electroless deposition method has been employed for the synthesis of silver nanotubes using porous anodic aluminium oxide as templates, by which high-yield silver nanotubes with length over ten microns have been synthesized.     

Templating and supersaturation-driven anti-templating: principles of biomineral architecture

The structural synergy between biominerals (CaCO(3), hydroxyapatite) and biosubstrates were examined for the first time. The templating effect of substrate and a newly identified supersaturation-driven interfacial structure mismatch effect were identified in the context of a new nucleation model. It follows that the heterogeneous nucleation which corresponds to a good structural match and synergy between biominerals and substrates will promote an ordered, compact, and tough complex biomineral structure, and occur only at low supersaturations, whereas at high supersaturations the heterogeneous nucleation associated with a poor structural match and synergy between biominerals and substrates will become dominant due to supersaturation-driven interfacial structural mismatch. The latter normally results in a disordered and porous structure. A phenomenon, so-called microgravity-driven homogeneous nucleation, was also examined. It turns out that microgravity will suppress convection and consequently promote homogeneous-like nucleation during biomineralization. This could be responsible for microgravity-induced osteoporousis.     

Novel chiral imidazole cyclophane receptors: synthesis and enantioselective recognition for amino acid derivatives

Novel chiral imidazole cyclophane receptors were synthesized by highly selective N-alkylation of the imadazolyl 1N-position of the bridged histidine diester 2 with the dibromide in the presence of NaH; these receptors exhibit good chiral recognition toward the enantiomers of L- and D-amino acid derivatives (up to KD/KL = 3.52, delta delta G0 = -3.11 kJ mol-1) in CHCl3 at 25.0 degrees C.     

Black Hole Entropy: Membrane Approach

The wall contribution character of the Bekenstein–Hawking entropy in the brick-wall model leads us to propose a new method of computing the entropy of a black hole. In our model, the entropy is attributed to the dynamical degrees of the field covering the two dimensional membranes just outside the horizon. A cutoff different from the model of 't Hooft is necessarily introduced. It can be treated as an increase in horizon because of the space–time fluctuations. It is also shown that our method can be applied to the nonstatic case, such as Vaidya–deSitter space–time, and the final result relies on a time-dependent cutoff different from the brick-wall model.